Gyroscopic horizon allowing the reading of great longitudinal inclinations



y 9, 1940- c. H. H. RODANET 2,297,414

G YROSCOPIC HORIZON ALLOWING THE READINGOF GREAT LONGITUDINAL INCLINATIONS Filed Sept. 28, 1938 3 Sheets-Sheet 1 HEHM RODAN wwafide m ms July 9, 1940. c. H. H. RODANET 2,297,414

GYRDSCOPIC HORIZON ALLOWING THE READING OF GREAT LONGITUDINAL INGLINAT IONS Filad Sept. 2a, 1938 s Sheets-Sheet 2 \NV ENTOR= CHARLES HILMRE HENRI RODANET A'rronnevs y 9, 1940- c. H. H. RODANET 2,207,414

GYROSGOPIC HORIZON ALLOWING THE READING OF GREAT LONGITUDINAL INCLINATIONS Filed Sept. 2a, 1958 s Sheets-Shet .Fie117;

ATTORNEY s mvzmow I \R CHARLES HS AN E.

Patented July 9, 1940 UNlTED* -STATES PATENT oar-ice 'GYROSCOPIC HORIZON ALIiOWlNG THE READING OF GREAT LONGITUDIN moLmanoNs Charles H ilaire Henri mutt, Neuilly-sur- Selne, France, assignor to Socit Anonyme: Jaeger Aviation, Levallols Perret (Seine).

France Application September as, 1938', Serial No. 23am In France October 20, 1937.

6 Claims. Y (01. 33-204 The problem has already been set down of establishing gyroscopic horizons which do not get out of orderduring aerobatics such as the figures so-called loopings" or horizontal spinnings, and it has been solved. Gyroscopic horizons even exist which continue to operate after so-called Immelmann turnings which consist in effecting a half-tum every successive-execution of a half-looping and of a half-horizontal spin-' ning; but these apparatus do not allow of reading great longitudinal inclinations, the index leaving the reading zone after a displacement of the order of 45. In the apparatus allowing the reading of great longitudinal inclinations: the

index is carried by a lever having a groove; an

lar to the direction of advance (half-looping) and of a rotation of 180 about the longitudin axis (half-horizontal spinning). Y It will also be noted that, when flyingnwith visibility, the pilot efiecting a half-looping when rising isees successively. the natural horizon:

--:-lowering relatively to him,. disappearing towards the lower part of his face,

reappearing towards face (the ground up, the sky down, relatively I to hisposition in space), i

and coming back again in front of his eye when lowering (the ground up, the sky down, relatively to his position inv space).

when flying without visibility. it is therefore necessary that the artificial horizon should:

lower, disappear downwardly, reappear upwardly,.,

lower again to come back to its normal posltion. i v

The improvements according to the invention,

which give a solution of the problem previously indicated, relate to 'an' artificial horizon of the gyroscopic typ allowing, moreover, the reading 01' great longitudinal inclinations, that is'to say .comprising, in particular, an index carried bya gearing down lever pivoted on a member mountsaid lever. the upper part of his 'ed so as to freely rotate about an axis parallel to the longitudinal axis .of the airplane and which constitutes-a support for the horizontal transverse suspension axisoi the gyroscope.

In its general principle, the invention consists in combining with the gearing down lever, means rigid with the transverse suspension axis of the gyroscope and which, in normal position for horizontal flight, are symmetrical both-relatively to the transverse 'axis and to the vertical plane passing through this axis so that, after a displacement of the airplane of 180' about a horizontal axis perpendicular to the direction of advance followed by a rotation oi 180 about the longitudinal aXis any subsequent displacement f the lever should be correctly effected.

The means, symmetrically arranged both rela- ;tively to the transverse suspension axis of the gyroscope and to the vertical plane passing through this axis, can be of any type whatever, electric, magnetic, mechanical, hydraulic, pneumatic or other means.

A-particularly advantageous embodiment 18 characterized by the fact that these means are arranged in a vertical plane perpendicular to the transverse suspension axis oi-the gyroscope and are constituted by two permanentmagnets having substantially the shape of two half-circumferences oi the same radius, co-axial and.

symmetrically arranged relatively to a horizontal diameter, a bar made of soft iron, rigid with the lever being arranged opposite ;the air-gap or polar space the nearest to the pivotal point of -In another embodiment, of the mechanical type, the symmetrically arranged means, as previous ly indicated, are constituted by a groove provideii in a plate controlled by the gyroscope and in which engages a roller the spindle of which is guided in a longitudinal groove formed in the lever carrying the horizon, the spindle being restored in thedirection of the pivotal point by a ht spring. v

Another improvement consists in neutralizin one of the magnetic fields created between the, poles of reverse name of these magnets, poles which are placed opposite each other, through the mediumxoi a fixed screen.

In a form ot construction the fixed screen is constituted by a small plate arranged opposite the polar space the'iarthest from the pivot pin or, the lever carrying the indicating pointer.

The accompanying drawings illustrate, on the one hand, a lmown apparatus and, on the other hand, by way of example only, improved apparatus according to the invention.

' artificial horizon improved, according to the in vention, these figures respectively correspond- Figs. 1, 2 and 3 diagrammatically illustrate a known artificial horizon, these figures showing the position of the various members respectively:

in horizontal flight, after a rotation of 180 about a horizontal axis perpendicular to the direction of advance, and after a rotation of 180 about the longitudinal axis of the airplane.

Figs. 4, 5 and 6 diagrammatically illustrate an ing to Figs. 1, 2 and 3.

Fig. 7 is a diagram.

Fig. 8 is a general perspective view of a practical embodiment of the gyroscopic artificial horizon diagrammatically illustrated in Figs. 4, 5 and 6.

Fig. 9 is a general elevation with partial vertical section of the apparatus illustrated in the preceding figure-the airplane slightly nose-divins Fig. 10 is a front view of the apparatus. Figs. 11 and 12 are diagrammatic details of a /mechanical embodiment according to the in- Fig. 16 is a general longitudinal elevation of I another embodiment, the casing being sectioned according to line XVI--XVI of Fig. 17.

Fig. 1'! is a plan view corresponding to the preceding figure, the casing being sectioned according, to line XVII--XVII Of this figure.

' pivotally mounted in a second support about an axis 22 perpendicular to the axis YY. This second support is freely journalled about an axis x parallel to the longitudinal axis of the airplane with which it is rigid, the axis XX bein perpendicular to the axis ZZ.

A lever 2, pivotally mounted about a pin 3 on the I and carries a reference mark or arcuate bar 5 which moves opposite a spherical cap 6 rigid with the second support. n

An eccentric 1, fast on the axis ZZ rigid with the first support, is eiigagedin the oblong port 4.

In normal horizontal flight, the eye of the pilot being located at 8, the various members occupy the position illustrated in Fig. 1, the airplane moving in the direction of the arrow F. v

When the pilot causes the airplane to eiiect a rotation of 180 about a horizontal axis, perpendicular to the direction F oi advance (halilooping), the various members occupy. after such a displacement and relatively to the eye .8 ofthe observer, the position illustrated in Fig. 2. In.

this position, the upper and lower parts A and B of the cap 6 are reversed,- the eccentric 'I and the port 4 having been] subjected to a relative displacement or 180.

The pilot then eflecting a'rotation of 180 about the longitudinal axis or the airplane (half-horisontai spinning) the various members come to the position illustrated in Fig.- 3.

It willbe noted that, in said 'Fig. 3, the eccentricity of the eccentric I relatively to the pivot pin 3, is arranged in reverse direction to that it The apparatus diagrammatically illustrated in Figs. 4, 5 and 6, which substantially correspond to Figs. 1, 2 and 3 will now be described. a

In this embodiment, on the axis Z are rigidly mounted two arcuate permanent magnets l4 and I5 arranged according to one and the same circumierence on either side oi a horizontal diameter, the air-gaps being'indicated at 1 and 1 On the balanced lever 2, pivotally mounted at 3 and carrying the horizon bar 5, is mounted a bar made of soft iron 11.

In normal position for horizontal flight, the various members occupy the position illustrated in Fig. 4, the eye oi the pilot being located at 8 and the airplane moving in the direction of the arrow F.

When the pilot causes the airplane to eflect a rotation of 180 about a horizontal axis perpendicular to the direction F of advance (half-looping), the various members occupy, after such a displacement and relatively to the eye 8 of the observer, the position illustrated in Fig. 5, the soft iron bar I! is now located, no longer opposite the air-gap F, but opposite the air-gap I In these conditions, any further displacement of the airplane will be correctly indicated. In fact,

if from the position indicated in .Flg. 5, the pilot then effects a rotation of 180 about the longitudinal axis of the airplane (half-horizontal spinning) the various members come to the position' illustrated in Fig. 6 which exactly corresponds to Fig. 5.

As indicated in the preamble, ii the pilot effects a half-looping when rising during flight without visibility, it is necessary that the artificial horizon should lower, disappear downwardly, reappear upwardly and againlower to return to its 1 normal position. Consequently, referring to Fig. second support, is provided with an oblong port- 7, and by marking in ordinates the successive positions oi the artificial horizon opposite'its gradnation, a curve must be obtained having the aspect indicated in said Fig. 7.

There is therefore discontinuity at this discontinuity is obtained by the apparatus diagrammatically illustrated in Figs. 4, 5 and 6. In fact, for a displacement slightly greater than Min of the airplane (quarter of looping when rising) -the air-gap 1 has come to the lower part and the diagram of which is given in Figs. 4, 5 and 6.

' at 1 and I This apparatus comprises a gyroscope I which rotates about a vertical axis YY in a first support pivotally mounted in a second support l about an axis ZZ, perpendicular to the axis YY. This second support is freely iournalled, about an axis XX, in a third support lirigid with the airplane, the axis x being parallel to the longitudinal axis of said airplane. are rigidly mounted thetwo arcuate permanent magnets 14 and IS, the air-gaps being indicated On the support it! is pivotally mounted, about a spindle 3, the lever 2 carrying the horizon bar 5 and the soft iron bar l'l, lever-2 being balanced by a counterweight i8.

On the support I0 is also mounted, through the medium of arms i9, a spherical cap 6 comprising two reference marks 2| and 22 constituted by slits, a horizontal silhouette 23 of an airplane and graduations 24 and 25 connecting'the reference marks 2i and 22 according to a vertical diameter.

Moreover, opposite either simply the reference mark 2|, or both the reference marks 2i and 22, are arranged graduations 26 carried by an annular plate 21 secured on a casing 28 rigid with the airplane, a protecting'glass plate being provided at 29.

In Figs. 9 and 10, the airplane is illustrated descending, the horizon bar S being in this case located above the silhouette 23. g L

The operation of this artificial horizon of the gyroscoplc type is identical to that described with reference to Figs. 4, 5 and 6. If the airplane takes a descending position, the various members occupy the position illustrated particularly in Figs. 9 and 10. If the airplane eifects successivelya rotation of 180 about a horizontal axis perpendicular to its direction of advance and a rotation of 180 about its longitudinal axis, the unit comprising the casing 28 is moved so that the soft iron bar i 'l is now located, no longer opposite'the air-gap 1, but opposite the air-gap I In these conditions, any further displacement of the airplane will be correctly indicated. In case of a lateral inclination, the casing inclines with its graduation 26 relatively to reference marks 2 i22 which always remain in a vertical plane.

If the silhouette 23 is traced on the cap *6, in-

case of a lateral inclination of the airplane, said silhouette remains parallel to the horizon.- bar 5. the indication of lateral inclination being given solely. by the reference mark 2i and the graduation 26. On the contrary, if the silhouette 23 is traced on the glass'fplate 29, rigid with the easing 28 rigidly secured to the airplane, the indication of inclination is given not only by the reference mark 2| and the graduation 26, but also by the relative angular position of the silhouette 23 and the horizon bar 5. .The arrangement of the silhouette 23 on the glass plate29 seems to be preferablen 1 It will be-noted that thesupport of the gyroscope can take all positions relatively to the frame without ever abutting against the latter; Whatever may be the position of the airplane, the axis of the gyroscope alwaysremains vertical. The rectifying system (secondary pendulum or the like), ensuring or ie-establishing the perfect verticality of the axis of the gyroscope, acts only for correcting very small variations dueto the friction of the pivotal joints. 'In known devices, on the'contrary, in which use is made of abutments, the rectifying system takes a relatively is a serious inconvenience.

On the axis Z atively to the support ll.

Another embodiment will now be diagrammatically described which constitutes a mechanical solution givingall the technical eflects of the magnetic embodiment illustrated in Figs. 8, 9 and 10.

This mechanical embodiment, shown in Figs. ll

to 15, comprises a plate '30 rigidly secured on the of which is guided in a longitudinal groove 33 formed in the lever 2 pivotally mounted at 2 and carrying the reference horizon mark 6. The axis Z is restored, in the-direction of the axis 2. by a light spring 34 mounted at its ends on both axes.

In normal position for horizontal flight (Fig. 13) the grooves and II coincide. During change of inclination in elevation, the relative (and not just at because of friction), the, spring 34 relaxes (see Fig. 15) and compels the horizon to effect the required discontinuity indicated in Fig. 7.

Figs. 16, 1'7 and 18 relate to a modification of theapparatus illustratedin Figs. 8, 9 and 10.

This modification comprises a gyroscope I the rotor of which'is arranged in a fluid-tight,

casing 32. The rotor rotates about an axis Y-Y which tends to coincide with the vertical of the place ove'ri-which the airplane is flying. Said axis Y-Y is inounted in the fluid-tight casing 32- axis Z and in which is provided an oblong port 1*. In this port is engaged a roller 3! the spindle I2 I which constitutes a flrst pivoted support, in a second support Ill, about an axis Z-Z, perpendicular to Y'Y and to the longitudinal axis of the airplane. This second support is freely journailed about an axis X-X in a third support ll rigid with the airplane, the axis X-X being parallel to the longitudinal axis of said airplane. 0n

tthe'axis 33 which materializes the axis Z-Z, are

rigidly mounted the two arcuate permanent magnets it and I5, the air-gapsbeing indicated at I and i The lever 2, carrying the indicating pointer ii,

is pivotally mounted'on a spindle 3 rigid with the support ill, the unit formed by the leverand the pointer being balanced by a counterweight la. The lever 2 carrying the pointer 5 is con-. trolled, as indicated, by the two magnets 14 and it in the shape of half-rings. The poles of re-. verse names of these magnets are placed opposite.

each other and, in the two intervals 1 and I exist two magnetic fields which can act' on a bar or blade made of soft iron lever 2.

According to the presentdnvention, one only of the magnetic fields acts at a-time on the bar I1,

ll secured on the the other-being neutralized by a fixedi'screen' 3i carried by the su rt l0.-

By this device 5. obtained a smooth audaccurate actuation of the lever 2 andconsequently, of the pointer 5, the latter indicating on the cap 6 forming dial, all the relative positions which may be assumed by the axis of the gyroscope relthe arms of said fork constituting bearings for.

said transverse shaft arranged at right angles to It is to be noted, particularly, that this absence of mechanical connection, in addition to the advantages previously mentioned, assemblage by universal joint of the gyroscope and impossibility for the latter to abut against the fork or support III which supportsit, allows the airplane to effect an aerobatics (loopings, horizontal spinnlngs,

on the fork of the gyro casing by means Immelmann turns) without the axis of the gyroscope departing from the vertical and by always giving correct indications, which constitutes an appreciable progress over existing apparatus.

What I claim as my invention and desireto secureby Letters Patent is:

- 1. In a gyroscopic horizon for airplanes and of -the type comprising a gyro casing provided with a transverse shaft, a fork journalled parallel to the longitudinal geometrical axisof the airplane the longitudinal geometrical axis .of the, airplane, in combination: a lever mounted on the fork of the gyro casing by means of a pivOtthegeOmetrical axis of which is parallel to the geometrical axis of the transverse shaft, a plate secured on the transverse shaft, means for producing between said lever andthe plate a connecting force the point of application of which on the lever is always located for all positions of the craft about its transverse axis on one and the same side of an imaginary plane containing the geometrical axis of the transverse shaft and-at right angles to the imaginary plane determined by said geometrical axis of the transverse shaft and the geometrical pivotal axis of the lever. V

2. In' gyroscopic horizon for airplanes and of the type comprising a gyro casing provided with a transverse shaft, a fork iournalled parallel the said lever, and two arcua to the longitudinal geometrical axis of the airplane the arms of said fork constituting bearings for the said transverse shaft arranged at right angles to the longitudinal geometrical axis of the airplane; in combination: a lever mounted on the fork of the gyro casing by a pivot the geometrical axis of which ls-parallel to the geometrical axis of the transverse shaft,- a soft iron bar rigid with said lever, and two arcuate permanent magnetsrigid with said transverse shaft having their ends separated to form air gaps normally lying in a horizontal plane, said 's'oft iron bar being arranged adjacent the air gap normally nearest the pivot of said lever.

3. In a gyroscoplc horizon for airplanes and of the type comprising a gyro casing provided with a transverse shaft, a fork journalled'parallel to the longitudinal geometrical axis of the airplane the arms of said fork constituting bearings for the said transverse shaft arranged at right angles to'thelongitudinal geometrical axis of the airplane, in combination: a lever mounted on the fork of the gyro casing by a pivot the geometrical axis of which is parallel to the geometrical axis of the transverse shaft, a soft on bar rigid with permanent magnets in the form of two half-circumferences having the same radius, co-axial and symmetrically arranged relatively to a horizontal geemetrical plane passing through the geometrical axis-pf the transverse shaft having their ends separated to form air. gaps normally lying in a horizontal plane, said magnets being arranged on either side of said plane and being rigid with said shaft, said soft iron bar being arranged adjacent the air gap normally nearest the pivot of said lever.

4. In a gyroscopic horizon for airplanes and of the type comprising a gyro casing provided with a transverse shaft, a, fork journalled parallel to the longitudinal geometrical axis of the airplane the arms of said fork constituting bearings for the said transverse shaft arranged at right angles to the longitudinal geometrical axis of the airplane, in combinationz a lever mounted of a pivot the geometrical axis of which is parallel to the geometrical axis of the transverse shaft, said lever being provided with a horizon bar movable opposite a graduation traced on a spherical cap rigid with said fork, a soft iron bar rigidsvith said lever, and two arcuate permanent magnets in the form of two half-circumfer'encw having the same .radius, co-axial and symmetrically ar ranged relatively to a horizontal geometrical plane passing through the geometrical axis of the transverse shaft having their ends separated to form alr gaps normally lying in a horizontal plane, said magnets being arranged on either side ,of said plane and being rigid with said shaft, said metrical axis of the transverse shaft, said lever being provided with a'horizon bar movable opposite a graduation traced on a spherical cap rigid I with said fork, a soft iron bar rigid with said .lever, two arcuate permanent magnets in the form of two half-circumferences having the same radius, co-axial and symmetrically arranged relatively to a. horizontal geometrical plane passing through the geometrical axis of the transverse shaft: having their ends separated to form air gaps normally lying in a horizontal plane, said magnets being arranged on either side of said plane and being rigid with said shaft, said salt iron bar being arranged adjacent the, air gap normally nearest the pivot of said lever, and a screenrigid with said fork for-neutralizing one.

of the magnetic fields created between the poles of opposite sign of said magnets.

6. In a gyroscopic horizon of the type comprising a gyro casing provided with a transverse shaft, a fork joumalled parallel tothe longitudinal geometrical axis of the airplane the arms of said fork constituting bearings for the said transverse shaft arranged at right angles to the longitudinal geometrical axis of the airplane, in combination: a lever mounted on the fork of the gyro casing by means of a pivot the geometrical axisof which is parallel to the geometrical axisof the transverse shaft said lever being formed with a first groove, 9. plate rigid with said transverse'shaft and formed with a second horizontal groove symmetrical relatively to the geometrical axis of said transverse shaft, a roller simultaneously engaging both said first groove and said second groove, a shaft for rotatably receiving said roller, and. a springmrging said shaftandroller in the direction of the pivot of said lever. t

CHARLES HENRI IODANET.

for airplanes and 

